To fulfill the requirement of the IMT-Advanced (International Mobile Telecommunications-Advanced), a peak data rate up to 1 Gbits/s is supported, and it is already agreed currently that the carrier aggregation (CA, Carrier Aggregation, also referred to as carrier aggregation) technology is used as a system bandwidth extension method for a 3GPP LTE-ADVANCED (LTE-A, LTE-Advanced) system. The carrier aggregation technology aggregates multiple component carriers (CCs, Component Carriers) into a larger bandwidth (for example, higher than 20 MHz) to support a high data transmission rate. For example, five 20-MHz component carriers may be aggregated into a downlink transmission bandwidth with 100 MHz.
To reduce blind detection complexity of a UE (User Equipment, user equipment) and reduce interferences among cells, a PDCCH (Physical Downlink Control Channel, physical downlink control channel) monitoring set and a PDSCH (Physical Downlink Shared Channel, physical downlink shared channel) set may be divided from multiple CCs. The CCs in the PDSCH set are component carriers used by the UE for receiving and sending data within a certain period of time. The component carrier is a downlink component carrier, an uplink component carrier or an uplink/downlink component carrier pair. The CCs in the PDCCH monitoring set are component carriers for sending scheduling information to the UE. Specifically, the scheduling information is transmitted through PDCCH signaling. The PDCCH monitoring set may be a subset of the PDSCH set. For a UE, the PDCCH monitoring set of the UE is a component carrier set on which the UE performs PDCCH monitoring to obtain scheduling information. For example, it is assumed that 5 component carriers exist currently, the component carriers are CC1 to CC5, the PDSCH set may be formed of 4 component carriers CC2 to CC5, and the PDCCH monitoring set may be formed of two component carriers CC2 and CC3. That is, when the UE uses four component carriers CC2 to CC5 for receiving and sending data, the UE may only monitor PDCCH channels of CC2 and CC3 to acquire scheduling information on CC2 to CC5.
During activation or configuration of the CC, how to manage the PDCCH monitoring set and implement monitoring on a corresponding CC becomes a problem.